ZetaTalk: Climbing WaterNote: written on Jun 15, 1999.

Those who have witnessed tidal bore roaring up a ravine are astonished
that water does not seem to respect the relative sea level during those
times. What makes the water climb? Water pressure drives water to climb above
its level because at the point where the pressure build, it takes the
easiest path. When the force of pressure is extreme, compressing the water
at lower levels, the path of least resistance is taken. During a tidal
wave, this path is away from the bulk of water. A tidal wave
moves inland until one of two situations occurs:

the level to which it has climbed is higher than the level elsewhere,
and the wave recedes, or

the pressure behind the wave decreases.

Where tidal waves meet mountains, this can result in tidal bore up
ravines. Where tidal waves flow inland, this results in a flood tide going
hundreds of miles inland. Where the tidal wave finds foot hills or
barriers, the force of the wave is broken such that it is slowed, allowing
a reduction in pressure behind the wave to arrive before the wave moves
far inland. But where the tidal wave finds virtually no barriers, due to
the land being flat, it becomes water on the move, and this very momentum
carries it far inland, and above a height that would otherwise be
expected.

Note: below added during the Nov 30, 2002
Live ZetaTalk IRC Session.

There is more to the level that water rises than simply water finding its
level. Tidal bore carried water up-river in a rush, rising above
the sea level with force, for many miles. Tidal bore
carries water up ravines, in some cases shooting almost straight
up, appearing in a gusher at the plateaus overhead. One factor to
consider is the force or pressure that water is under, and this
is equivalent to the water higher, elsewhere. This is the factor that
allows cities to have tap water, due to water stored at a high
point in the vicinity, which then pushes out into pipes. Water on the move
does more than just push forward, it also creates a void behind it. At
first, this water is on the move because there is pressure
behind it, like sloshing water in the Gulf. But then, the force of this
moving water takes on a life of its own. It has momentum, and moving
forward, creates a void behind it, thus drawing the water in the
direction of motion, thus continuing the motion. Thus, rolling across the
flat low lands such as the State of Texas, and moving hundreds of miles
inland, on a roll, it does not simply stop when it starts to
reach foothills. Why would it stop? Because the overall elevation is more
than the sea level? Weigh this, with the force of water, all on
the move, behind the lip of the flood tide. This water on the move is
greater than the resistance in front of it, so it continues.